Hybrid ray‐mode formulation of ducted propagation

摘要: High‐frequency propagation in waveguides or ducts can be formulated terms of a guided mode ray expansion. When the duct is very wide, excessively large number modes rays often necessitates truncation resulting series. This paper examines problem and shows that hybrid formulation, properly chosen modes, account for remainder field either case. The representation has appealing physical content few lowest collective behavior with many reflections, while lower‐order higher‐order modes. Other representations involving rays, canonical integral, continuous spectrum, nearfield perturbation are also examined. Numerical comparisons specific example show utility range validity these alternative representations.